Matlab h5read and Python h5py Conflict

We are testing out the Matlab Library Compiler in order to produce Python libraries of some of our Matlab functions. We work with the HDF5 file format and therefore invoke the Matlab h5read function frequently.

We are encountering errors when a Python script imports h5py as well as our in-house package which calls h5read.

Some details:

Matlab version R2021b

Python 3.9.18

h5py version 3.10.0

We have tested with a simplified package (called here test_h5read)and a simple python script in order to reproduce the issue.

In the python script we have the following :

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import test_h5read

import h5py # Without this import statement, the script executes successfully

# When importing h5py, below error occurs.

pkg = test_h5read.initialize()

Raw_cube = 'test_cube.h5'

pkg.test_h5read(Raw_cube, nargout=0)

pkg.terminate()

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Error Output:

python .\testMatlabPkg.py

One or more output arguments not assigned during call to "h5readc".

Error in h5read (line 93)

Error in test_h5read (line 5)

Traceback (most recent call last):

File "C:\Users\swdevs\Dev\TestMatlabPackage\testMatlabPkg.py", line 7, in <module>

pkg.test_h5read(Raw_cube, nargout=0)

File "C:\Program Files\MATLAB\MATLAB Runtime\v911\toolbox\compiler_sdk\pysdk_py\matlab_pysdk\runtime\deployablefunc.py", line 79, in __call__

ret = futureresult.FutureResult(self._cppext_handle, future_tuple, nlhs,

File "C:\Program Files\MATLAB\MATLAB Runtime\v911\toolbox\compiler_sdk\pysdk_py\matlab_pysdk\runtime\futureresult.py", line 135, in result

raise e

File "C:\Program Files\MATLAB\MATLAB Runtime\v911\toolbox\compiler_sdk\pysdk_py\matlab_pysdk\runtime\futureresult.py", line 123, in result

raise e

File "C:\Program Files\MATLAB\MATLAB Runtime\v911\toolbox\compiler_sdk\pysdk_py\matlab_pysdk\runtime\futureresult.py", line 112, in result

self._result = self._cppext_handle.getFEvalResult(self._future_tuple,

matlab_pysdk.runtime.MatlabRuntimeError: An error occurred when evaluating the result from a function. Details:

File C:\Program Files\MATLAB\MATLAB Runtime\v911\mcr\toolbox\matlab\imagesci\h5read.m, line 93, in h5read

File C:\Users\swdevs\AppData\Local\Temp\swdevs\mcrCache9.11\test_h0\test_h5read\test_h5read.m, line 5, in test_h5read

One or more output arguments not assigned during call to "h5readc".